1. Field of the Invention
This invention relates to a spike tire to be used for securing safe travel of a vehicle on frozen and snowy roads.
2. Description of the Prior Art
In snowy cold districts, tire chains and spike tires are used to drive motor vehicles safely on frozen and snowy roads. In this connection, lately there is a trend that in most cases the spike tires which have spikes or anti-skid elements constantly projected on the surface of a tire tread are preferred to the chains which are fitted on tires only when road surfaces are frozen or snowed, because of the problems of putting on and taking off the chains.
However, partly because of recent development of snow removing techniques and partly because of increases in the amount of traffic, road surfaces are often exposed even after snowfalls, shortening the travel distances which need spike tires to a considerable degree. For instance, in Hokkaido, a northern district of Japan, it is assumed that the distance which requires spike tires is as small as 5% of the total travel distance.
If used on such non-frozen, snow-free roads, the conventional spike tires which have hard metal spike pins embedded in the tread faces give rise to problems such as damages and abrasive wear of road surfaces and pollution by the resulting dust. These problems occur commonly in cold snowy districts of various countries, and are generally dealt with by totally prohibiting the use of spike tires or restricting the use to a certain period. However, from a view point of safe travel of vehicles in snowy districts, the use of spike tires is very effective, and therefore it is desirable to solve the above-mentioned problems in a way to permit the use of spike tires on non-frozen bare roads.